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is this enough support to prevent slab bulging?

mikeysp | Posted in General Questions on

Editied for clarity.

Hi, we are pouring a floating slab in zone 4a for our shop.

Do I have enough kickers to prevent bulging for my slab?

1-1/2″x 12″ actual dimension pine form board.
2×4 waler? below form top edge.
Kickers every 4ft.
I will also place about 5″ of the soil used for pad along bottom edge of form board. 
At the 8ft O.C. concrete piers I used a single 3″ Tapcon to hold form board height while I did the real supports.

Slab details:
5″ concrete
2″ recycled 25psi XPS (2 pieces of 1″).
4″ gravel

Thank you.


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  1. mikeysp | | #1

    I reworded the question for brevity and clarity hoping I can get some advice.

    1. Expert Member
      MALCOLM TAYLOR | | #2


      I am waiting for the weather to improve to pour two slabs with much less support than that one. With a dry mix there should be next to no lateral pressure on the forms. The situation is not the same as pouring stem-walls, which have to carry the weight of a considerable depth of concrete.

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